Hi,Thought it may help to shorten my original question to a single point :I can understand it when X and Y are specified as vectors in the following command i.e. X=1:dim(Z,2) and Y=1:dim(Z,1)surface('XData',X,'YData',Y,'ZData',Z,'CData',C)How do I interpret their specification as matrices? For example, what does the following mean :surface([-1 -1; -1 -1], [-1 1; -1 1], [-1 -1; 1 1], ... 'FaceColor', 'texturemap', 'CData', cdatar );I will be grateful for any help that I can get.Thanks,Ravi